Benchmark: for loop comparison test modernized ES6

HTML Preparation code:

<script src="https://cdn.jsdelivr.net/lodash/4.16.0/lodash.min.js"></script>

Script Preparation code:

var values = [{a: 30310}, {b: 100303}, {c: 3040494}];

Tests:

lodash.forEach
let count = 0; _.forEach(values, function(v,i) { if (v.a != null) { count++; } });
native
let count = 0; for (let i = 0; i < values.length; i++) { if (values[i].a != null) { count++; } }
ES5 forEach (cannot break;)
let count = 0; values.forEach(function(v,i) { if (v.a != null) { count++; } });
ES5 for-in
let count = 0; for (value in values) { if (value.a != null) { count++; } }
ES6 for-of
let count = 0; for (value of values) { if (value.a != null) { count++; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash.forEach
native
ES5 forEach (cannot break;)
ES5 for-in
ES6 for-of

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its test cases.

**What is tested:**

The provided JSON represents a JavaScript microbenchmark that compares different approaches to iterate over an array of objects. The benchmark tests four methods:

1. `_.forEach` from the Lodash library
2. A native for loop
3. ES5 `forEach` with a callback function (note: this has a limitation due to the way it breaks out of loops)
4. ES5 `for-in`
5. ES6 `for-of`

The benchmark tests the performance of these methods on an array of objects (`values`) containing three properties (`a`, `b`, and `c`).

**Options compared:**

Here are the different approaches being compared:

1. **Lodash's `_forEach`**: This method is part of the Lodash library, which provides a collection of useful functions for functional programming.
2. **Native for loop**: This is a traditional way to iterate over an array using a `for` loop and an index variable (`i`).
3. **ES5 `forEach` with callback**: In ES5, `forEach` does not break out of loops like modern browsers do. Instead, it relies on the callback function to handle exceptions or break out of the loop manually.
4. **ES5 `for-in`**: This method uses the `in` keyword to iterate over the properties of an object. Note that this method is different from `forEach`, as it iterates over both numeric and symbolic property keys.
5. **ES6 `for-of`**: Introduced in modern browsers (including Chrome 106), ES6's `for-of` loop provides a way to iterate over iterable objects using a more concise syntax.

**Pros and cons of each approach:**

Here are some pros and cons for each method:

1. **Lodash's `_forEach`**:
	* Pros: Convenient, widely supported by libraries and frameworks.
	* Cons: Adds an extra dependency (the Lodash library).
2. **Native for loop**:
	* Pros: Fastest execution time, minimal dependencies.
	* Cons: More verbose code, requires manual index management.
3. **ES5 `forEach` with callback**:
	* Pros: Can be used in older browsers or environments where `for-of` is not supported.
	* Cons: Breaks out of loops manually using the callback function's `return` statement.
4. **ES5 `for-in`**:
	* Pros: Wide support across browsers and platforms, especially for legacy codebases.
	* Cons: Not designed for iterating over arrays; uses both numeric and symbolic property keys.
5. **ES6 `for-of`**:
	* Pros: Modern, concise syntax, efficient execution time.
	* Cons: Requires modern browsers or environments that support ES6+.

**Other considerations:**

* The Lodash library is included in the benchmark to make it easier for users who want to take advantage of its convenience and functionality.
* The `values` array is defined using an object literal, which makes it easy to iterate over its properties.

**Alternatives:**

For this specific benchmark, alternative approaches might include:

1. **Using `Array.prototype.forEach()`**: This method provides similar behavior to Lodash's `_forEach`, but without the additional dependency.
2. **Implementing a custom iterator**: Users could implement their own custom iterator using a `Symbol.iterator` function or a callback function, depending on their needs.

Keep in mind that the choice of approach depends on the specific use case, performance requirements, and personal preference.

Related benchmarks:

for loop comparison test modernized ES6 (version: 0)

Comparing performance of: lodash.forEach vs native vs ES5 forEach (cannot break;) vs ES5 for-in vs ES6 for-of

Created: 4 years ago by: Guest

Jump to the latest result

lodash.forEach

native

ES5 forEach (cannot break;)

ES5 for-in

ES6 for-of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):